The proposed program of research will increase our knowledge of cochlear function through a combination of theoretical and empirical studies addressing fundamental processes in ways that have both basic and translational implications. The program focuses on two interrelated areas: (1) the level-dependence of cochlear delays and (2) the effect on cochlear response growth at a particular frequency due to the presence of suppressors at other frequencies. Suppression and level-dependent latency share a common mechanism that is primarily responsible for cochlear compression. These areas represent features of normal cochlear function that are affected by cochlear hearing loss and potentially may be remediated by external hearing aids that incorporate sophisticated signal-processing strategies. The first two Aims of the proposal are to further understand (1) cochlear-reflectance generation and (2) the latency and masking of cochlear transients. Cochlear reflectance is defined as a transfer function between pressure waves entering and exiting the cochlea, and has advantages over other measures of cochlear responses. The remaining Aims are to determine the influence of (3) high-frequency suppression on cochlear distortion generators and (4) low- frequency suppression on cochlear compression. Through the work related to these four Aims, questions that possess both basic scientific interest and applied clinical relevance wil be answered by combined application of measurement and modeling efforts.